Method of and apparatus for straightening saws and steel plates



(No Model.) 4

T. BAKEWBLL.

Method of and Apparatus for Straightening Saws and Steel Plates.

No. 233,463. Patented Oct. 19, I880.

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THOMAS BAKEWELL, OF-PITTSBURG, PENNSYLVANIA.

METHOD OF AND APPARATUS FOR STRAIGHTENING SAWS AND STEEL PLATES.

SPECIFICATION forming part of Letters Patent No. 233,463, dated October 19, 1880.

Application filed August 16, 1880. (No model.)

To all whom it may concern:

Be it known that I, THOMAS BAKEWELL, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful ImprovedMethod of and Apparatus for Straightening Saws and other Steel Plates and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, forming a part of this specification, in which Figure 1 is a view of a saw-tempering furnace illustrating the operation of my improvement. Fig. 2 is an edge view of the saw-holders; and Fig. 3 is a plan View of one of the holders, showing how the saws are placed thereon.

Like letters of reference indicate like parts in each.

Among the final steps in the manufacture of saws are drawing the temper and straightening. With long saws this has been done by drawing the saw through a furnace between heated heavy dies by means of a chain hooked in a hole in the end of the saw and a pulley and crank. With short saws and circular saws these operations have been conducted separately. The straightening is done by hammering.

My invention consists in placing the saws between metallic-plates and drawing the latter through the tempering-furnace between heated dies. This operation is applicable to any kind of saws, and effects the double function of drawing the temper and straightening the saw at one operation.

To enable others skilled in the art to make and use my invention, I will now explain its operation.

The furnace a is of the ordinary form, having a stationary die, 11, a moving die, 0, afeedopening, d, a discharge-opening, e, a hook, a, chain g, Windlass h, and a crank, t'. In addition to these, I make use of holders k, which are two flat metallic plates of any desired size and shape, and having a hole, m, at the front end, to which the hook n is fastened. The

moving die is pivoted to a lever, l,in theusual manner.

The saws which require to be straightened and to have the temper drawn are too hard for use and very much warped and bent out of shape. I place them between the holders k, then raise the upper die, 0, and insert the forward end of the holder 70 through the open- 5 5 ing 01 between the dies b and c. When the proper degree of heat is indicated by the color of the heated dies I attach the hook at in the hole m and draw the holder slowly through the furnace between the dies. If the color of the dies indicates a variation of the heat, I hasten or retard the movement of the holder accordingly.

When the saws come out of the furnace they will be of the proper temper and perfectly straight, requiring no smithing or hammering whatever.

I estimate the saving thus accomplished at from twenty cents to one dollar for long saws and at from twenty-five cents to five dollars per saw for circular saws. In addition to this the saw is made much truer: than could be done by hand.

This method is also applicable with beneficial results to long saws, as it saves making a hole in them and makes them truer than when drawn through without the holders, and it prevents the breaking of the teeth on the dies, which often happens. Several circular and small saws can be straightened at once, thus effecting a further considerable saving and increasing the product.

Instead of a hole, the end of the holders may be grooved, roughened, or otherwise fitted for the attachment of the drawing mechanism by hook, clamp, or other device.

This invention is also applicable to the straightening of all tempered-steel plates, and as many such articles are used for various purposes in the arts I will not attempt to enumer- 9o ate them.

What I claim as myinvention, and desire to secure by Letters Patent, is-

1. The method of straightening saws and other steel plates herein described, consisting 1 other means of attachment for the drawing 10 of placing them between metallic plates or apparatus, substantially as and for the purholders and then drawing the latter through poses described.

between heated dies, substantially as and for In testimony whereof I have hereunto set 5 the purposes described. my hand. 1 2. The combination of flat metallic holders THOS. BAKEWELL. 1 and heated straightening-dies, substantially Witnesses: as and for the purposes described. JAMES H. PORTE,

3. The flat metallic holders having a hole or T. B. KERR. 

